Question

Please have a look at the code below.

Dim results As IEnumerable(Of Customer) = ExecuteDataReader( _
               "SELECT * FROM Customer WHERE Sales> @MinSales", _
          Sub(p) p.Add("@MinSales", SqlDbType.Double).Value = 10000.0, _
          Function(r) New Customer() With {Name=r("Name"), Address=r("Address"), Sales=r("Sales") })

For Each c As Customer in results
   '...
Next

In a previous question I posted, the answerer posted this code. I do not understand the sub(p) or function(r) part of the code.

Unfortunately I have no basis to search for an answer to this. Therefore I have posted this question after completing a limited amount of research.

What is meant by sub(p) and function(r) ?

Update 14:54

Please see below. What is meant by: (Of T) and ByVal castRow As Function(Of IDataRecord, T)?

Public Iterator Function ExecuteDataReader(Of T)(ByVal sql As String,
ByVal addParams as Action(Of SqlParameterCollection), ByVal castRow As
Funnction(Of IDataRecord, T)) As IEnumerable(Of T)

Answer 1

Lambda Expressions:

A lambda expression is a function or subroutine without a name that can be used wherever a delegate is valid. Lambda expressions can be functions or subroutines and can be single-line or multi-line. You can pass values from the current scope to a lambda expression.

Dim increment1 = Function(x) x + 1
Dim increment2 = Function(x)
                     Return x + 2
                 End Function